Enhancing the multicast performance of structured P2P overlay in supporting Massively Multiplayer Online Games

Scribe is a scalable application level multicast infrastructure. We have developed two techniques to improve the performance of Scribe in terms of latency and bandwidth distribution. The first technique identifies that the final hop of Scribe traffic path is largely selected without any proximity consideration and incurs the longest distance traveled. To overcome this, we introduce Proximity Neighbor Selection (PNS) into the final hop for latency improvement. The second technique builds a hierarchical two-level overlay. While PNS can be applied at both levels for latency performance, the bandwidth stress required by applications can now be distributed among the nodes in the higher level overlay. Our simulation using GT-ITM topology has shown that both techniques have improved the latency performance for more than 30 percent, and the two-level overlay has improved the bandwidth distribution up to 2.7 times, comparing with what can be achieved by a standard Scribe overlay. We have developed the techniques in the context of Massively Multiplayer Online Games (MMOGs). While Scribe provides a possible platform for the scalable deployment of MMOGs, game developers may leverage the techniques to enhance the design of real-time interactions between players in the game world

Re-engineering jake2 to work on a grid using the GridGain Middleware

With the advent of Massively Multiplayer Online Games (MMOGs), engineers and designers of games came across with many questions that needed to be answered such as, for example, "how to allow a large amount of clients to play simultaneously on the same server?", "how to guarantee a good quality of service (QoS) to a great number of clients?", "how many resources will be necessary?", "how to optimize these resources to the maximum?". A possible answer to these questions relies on the usage of grid computing. Taking into account the parallel and distributed nature of grid computing, we can say that grid computing allows for more scalability in terms of a growing number of players, guarantees shorter communication time between clients and servers, and allows for a better resource management and usage (e.g., memory, CPU, core balancing usage, etc.) than the traditional serial computing model. However, the main focus of this thesis is not about grid computing. Instead, this thesis describes the re-engineering process of an existing multiplayer computer game, called Jake2, by transforming it into a MMOG, which is then put to run on a grid

Peer-to-peer interactive 3D media dissemination in networked virtual environments

Ph.DDOCTOR OF PHILOSOPH

Scalable propagation of continuous actions in peer-to-peer-based massively multiuser virtual environments : the continuous events approach

Peer-to-Peer-based Massively Multiuser Virtual Environments (P2P-MMVEs) provide a shared virtual environment for up to several thousand simultaneous users based on a peer-to-peer network. Users interact in the virtual environment by controlling virtual representations of themselves, so-called avatars. Their computers communicate with each other via a wide area network such as the Internet to provide the shared virtual environment. A crucial challenge for P2P-MMVEs is propagating state changes of objects in the virtual environment between a large number of user computers in a scalable way. Objects may change their state on one of the computers, e.g. their position. Information about a state change has to be propagated via the peer-to-peer network to computers of other users whose avatars are able to perceive the object. Optimization algorithms for a scalable propagation of state changes are needed because of the very large number of users and the typically limited bandwidth of their Internet connections. This thesis describes an approach that optimizes the propagation of state changes caused by continuous actions. Continuous actions lead to multiple subsequent state changes over a given period of time. Instead of propagating each subsequent state change caused by continuous actions via the network, the approach propagates descriptions of the actions included in so-called continuous events. Based on the descriptions, the subsequent state changes are calculated and applied over time on each user's computer. Continuous events contain information about (1) the timing of calculations, (2) the spatial extent of the influence of the continuous action in the virtual environment over time and (3) the effect of the continuous action on influenced objects over time. The propagation and management of continuous events is performed based on the spatial publish subscribe communication model. Each user computer declares interest in a certain space in the virtual environment. If the space intersects with the spatial extent of the influence of a continuous event, the particular computer is provided with the continuous event. This thesis describes the basic concept of continuous events, presents a system architecture for support of continuous events in the context of a given target system model for P2P-MMVEs, and evaluates the continuous events approach based on a prototypical implementation of the system architecture